scholarly journals DEVELOPMENT OF ULTRA-SHORT HIGH INTENSITY LASERS FOR THE VISIBLE SPECTRA RANGE

2020 ◽  
Vol 17 (35) ◽  
pp. 739-752
Author(s):  
Hayder J. ABDULRAHMAN ◽  
Suzan B. MOHAMMED
Keyword(s):  
High Intensity ◽  
Laser Processing ◽  
Near Infrared ◽  
Laser Pulses ◽  
Dielectric Materials ◽  
Infrared Light ◽  
Near Infrared Light ◽  
Visible Spectra ◽  
Short Laser Pulses ◽  
Micro Tools

Ultra-short laser pulses are particularly suitable for processing micro tools made of ultra-hard and dielectric materials. Ultra-short laser pulses provide a contact-free and precise fabrication of heat-sensitive materials such as visible spectra range. Visible spectra range has unique properties, which makes it an essential material in the tool, jewelry, and semiconductor industries. The processing of visible spectra range by ultra-short laser pulses is complex, as visible and near-infrared light is generally not absorbed. However, the intensity of ultra-short laser pulses is extremely high, so that the absorption scales nonlinearly with the intensity and, thus, visible or near-infrared light can be absorbed. The complexity also results from many partially interdependent process variables, such as the repetition rate, pulse overlap, track overlap, and scan speed. Excellent knowledge of the process is, therefore, essential for the production of micro tools. To make the laser processing accessible to a broader user field, the operator can be supported by a computer-aided design (CAD). The aim of this research was to the modeling of an ultra-short high-intensity laser for the visible spectra range in different environments of the angle of incidence, scanning speed, pulse, and track overlap. The experimental process included ultra-short pulsed laser processing of visible spectra range and surface analysis concerning modifications and ablation of the ultra-short laser. Ablation volumes were analyzed for single pulses, multi-pulses, and pockets. Pump-probe experiments reveal transient optical properties such as transmission or reflectivity. It was concluded that ultraviolet laser pulses are best suited to induce damage or modifications to visible spectra range surfaces. Additionally, shorter wavelengths have further advantages such as potentially longer Rayleigh lengths and smaller spot sizes.

Investigation of Transient Signals in Nonuniform Media Based on Diffusion Approximation

2009 ◽  
Author(s):  
Sheng-gang Wang ◽  
Li-ming Ruan ◽  
Hong Qi ◽  
Xi-ying Wang ◽  
Bing-xi Li
Keyword(s):  
Optical Properties ◽  
Diffusion Approximation ◽  
Near Infrared ◽  
Short Pulse ◽  
Numerical Models ◽  
Optical Tomography ◽  
Laser Pulses ◽  
Biological Tissues ◽  
Infrared Light ◽  
Short Laser Pulses

With the development of the ultra-short laser technology, a new optical detection field based on the transient laser pulse signals will emerge in the future. Ultra-short laser pulses have been used in biological fields to obtain the optical properties of vivo tissues. There are many numerical models to simulate the propagation of short laser pulses in tissue medium. However, since most biological tissues show a high scattering and low absorption characteristics for near-infrared light, the most popular model is diffusion approximation method. Although with many limitations, its greatest advantage is higher computational efficiency. The propagation of short pulse laser in two dimension nonuniform medium is simulated based on the diffusion approximation model in present paper. The numerical method is validated by comparing the numerical results with the theoretical analysis results in semi-infinite uniform slab medium. Then diffusion approximation is used to simulate the transfer process of ultra-short pulses in two dimensional inhomogeneous medium. Finally, The influences of inclusions with different sizes and optical properties on time-resolved reflected signals are presented. This can help to choose suitable detection parameters in diffuse optical tomography.

An ordered copper nanowell-array film with near-perfect broadband absorption from ultraviolet to near-infrared light

2020 ◽  
Vol 59 (11) ◽  
pp. 110906
Author(s):  
Juan Shen ◽  
Yong Ren ◽  
Xinxin Zhu ◽  
Min Mao ◽  
Quan Zhou ◽  
...  
Keyword(s):  
Near Infrared ◽  
Infrared Light ◽  
Near Infrared Light ◽  
Broadband Absorption

scholarly journals Recent Near-Infrared Light-Activated Nanomedicine toward Precision Cancer Therapy

2021 ◽  
Author(s):  
Xiaowei Luan ◽  
Yongchun Pan ◽  
Yanfeng Gao ◽  
Yujun Song
Keyword(s):  
Cancer Therapy ◽  
Near Infrared ◽  
Infrared Light ◽  
Human Society ◽  
Near Infrared Light ◽  
History Of ◽  
The Universe

Light has witnessed the history of mankind and even the universe. It is of great significances to the life of human society, contributing to energy, agriculture, communication, and much more....

scholarly journals Au–ZnO Conjugated Black Phosphorus as a Near-Infrared Light-Triggering and Recurrence-Suppressing Nanoantibiotic Platform against Staphylococcus aureus

Pharmaceutics ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 52
Author(s):  
Atanu Naskar ◽  
Sohee Lee ◽  
Kwang-sun Kim
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Infections ◽  
Near Infrared ◽  
Au Nanoparticles ◽  
Synthesis Method ◽  
Antibacterial Properties ◽  
Black Phosphorus ◽  
Infrared Light ◽  
Resistant Bacteria ◽  
Near Infrared Light

Antibiotic therapy is the gold standard for bacterial infections treatment. However, the rapid increase in multidrug-resistant (MDR) bacterial infections and its recent use for secondary bacterial infections in many COVID-19 patients has considerably weakened its treatment efficacy. These shortcomings motivated researchers to develop new antibacterial materials, such as nanoparticle-based antibacterial platform with the ability to increase the chances of killing MDR strains and prevent their drug resistance. Herein, we report a new black phosphorus (BP)-based non-damaging near-infrared light-responsive platform conjugated with ZnO and Au nanoparticles as a synergistic antibacterial agent against Staphylococcus aureus species. First, BP nanosheets containing Au nanoparticles were assembled in situ with the ZnO nanoparticles prepared by a low-temperature solution synthesis method. Subsequently, the antibacterial activities of the resulting Au–ZnO–BP nanocomposite against the non-resistant, methicillin-resistant, and erythromycin-resistant S. aureus species were determined, after its photothermal efficacy was assessed. The synthesized nanocomposite exhibited excellent anti-S. aureus activity and good photothermal characteristics. The non-resistant S. aureus species did not produce drug-resistant bacteria after the treatment of multiple consecutive passages under the pressure of the proposed nanoantibiotic, but rapidly developed resistance to erythromycin. This work clearly demonstrates the excellent photothermal antibacterial properties of Au–ZnO–BP nanocomposite against the MDR S. aureus species.

π-Conjugated Copolymers Composed of Boron Formazanate and Their Application for a Wavelength Converter to Near-Infrared Light

2021 ◽  
Vol 54 (4) ◽  
pp. 1934-1942
Author(s):  
Yuki Kawano ◽  
Yoshinori Ito ◽  
Shunichiro Ito ◽  
Kazuo Tanaka ◽  
Yoshiki Chujo
Keyword(s):  
Near Infrared ◽  
Infrared Light ◽  
Wavelength Converter ◽  
Near Infrared Light ◽  
Conjugated Copolymers

Visible and near-infrared light activated azo dyes

2021 ◽  
Author(s):  
Huijuan Chen ◽  
Weijie Chen ◽  
Yan Lin ◽  
Yuan Xie ◽  
Sheng Hua Liu ◽  
...  
Keyword(s):  
Azo Dyes ◽  
Near Infrared ◽  
Infrared Light ◽  
Near Infrared Light
Sign in / Sign up

Export Citation Format

Share Document